1. Technical Field
The present invention relates to a switch device for turning on/off switches by operation of operation knobs, particularly a water proof type switch device for preventing intrusion of water into an interior of a case.
2. Related Art
A switch device for performing opening/closing control of windows, locking/unlocking control, and the like is provided in a vehicle such as an automobile. This type of switch device is generally arranged in a door arm rest, a center console, or the like.
As shown by the reference character 100′ in FIG. 12, the above switch device is provided with a case 11′, a cover 51′ covering an upper surface of the case 11′, and operation knobs 21′.
In FIG. 12, an arrow F indicates the front direction of the switch device 100′. Hereinafter, similarly, an arrow B indicates the back direction, an arrow R indicates the right direction, an arrow L indicates the left direction, an arrow U indicates the upward direction, and an arrow D indicates the downward direction. Therefore, FIG. 12 is a side sectional view of a case where the switch device 100′ is seen from the left direction L.
Electronic components such as switches 71′ and a circuit substrate 72′ are accommodated in an interior of the case 11′. Tube portions 12″ opening in the up and down direction and communicating with the interior of the case are provided on the upper surface of the case 11′. The operation knobs 21′ are attached to the tube portions 12″ so as to cover upper openings of the tube portions 12″. Further, the operation knobs 21′ are operably exposed from holes 52′ provided in the cover 51′.
In such a switch device 100′, in a case where rainwater intruding from a window left to be open, drinking water spilled from a container, or the like (hereinafter, these are collectively called as the “water”) is splashed onto the cover 51′, the water runs down to the upper surface of the case 11′ through clearances between the holes 52′ of the cover 51′ and the operation knobs 21′ and flows to the side of the tube portions 12″ as shown by arrows in the figure.
When an amount of the water flowing to the side of the tube portions 12″ is large, the water sometimes rises in clearances between the operation knobs 21′ and the tube portions 12″, and intrudes into the interior of the case 11′ through the openings of the tube portions 12″. The water intruding into the interior of the case 11′ becomes a cause of corrosion or short in the electronic components such as the switches 71′ and the circuit substrate 72′.
Therefore, in Japanese Patent No. 4312739, Japanese Patent No. 4280250, and Japanese Patent No. 4193824, a water proof type switch device for preventing intrusion of water into an interior of a case is proposed.
For example, in the switch device described in Japanese Patent No. 4312739, projections are provided in the vicinity of tube portions to which operation knobs are attached, and in a state that the operation knobs are not swung, lower ends of the operation knobs and upper ends of the projections face each other so as to have minute clearances. Accordingly, even when the water is brought in from an exterior through clearances between a cover and the operation knobs, a flow of the water to rise in clearances between the operation knobs and the tube portions is blocked by the projections.
In the switch device described in Japanese Patent No. 4280250, depressions are provided in the vicinity of tube portions to which operation knobs are attached, and lids covering part of the depressions are provided on the side of the tube portions of the depressions. Accordingly, even when the water is brought in from an exterior through clearances between a cover and the operation knobs, the water running down to an upper surface of a case enters the depressions, and then collides with the lids and circulates in a spiral shape in the depressions. Therefore, a flow of the water to rise in clearances between the operation knobs and the tube portions from the depressions is stopped by the lids.
In the switch device described in Japanese Patent No. 4193824, guide portions having slope surfaces sloping in the left and right direction are provided in the vicinity of front ends of operation knobs on an upper surface of a case. Accordingly, even when the water is brought in from an exterior through clearances between a cover and the operation knobs, the water running down to the vicinity of the front ends of the operation knobs on the upper surface of the case is discharged from opening ends of the guide portions to the left and right sides of the case along the slope surfaces of the guide portions. Therefore, a flow of the water to rise in clearances between the operation knobs and tube portions can be preliminarily prevented.